This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-206201, filed Jul. 21, 1999; No. 11-206203, filed Jul. 21, 1999; No. 11-206204, filed Jul. 21, 1999; No. 11-226342, filed Aug. 10, 1999; No. 11-361154, filed Dec. 20, 1999; and No. 2000-173897, filed Jun. 9, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a photovoltaic cell module tile composed of a tile used as a roofing material for a building and a photovoltaic cell module mounted thereon.
According to techniques described in Jpn. UM Appln. KOKAI Publications Nos. 62-52610, 1-148417, 4-28524, and 5-3430, Jpn. Pat. Appln. KOKAI Publication No. 11-1999, etc., a photovoltaic cell is mounted on a tile for use as a roofing material for a building, and solar energy is converted into electricity for practical use.
In the example described in Jpn. UM Appln. KOKAI Publications No. 62-52610, a depression in a shape that fits photovoltaic cells is provided in the upper surface of a sheathing material for tiles and outer walls, and the photovoltaic cells are set in the depression.
In the example described in Jpn. UM Appln. KOKAI Publication No. 1-148417, a photovoltaic cell is located on the surface of the lower part of a flat tile, and lead wires of the cell are led out through spaces on the reverse side of the opposite ends of the upper edge of the tile.
In the example described in Jpn. UM Appln. KOKAI Publication No. 5-3430, a photovoltaic cell is bonded to the surface of a tile, and an opaque sheet is separably attached close to the surface of the cell so that it can protect the cell during tiling operation.
In the example described in Jpn. Pat. Appln. KOKAI Publication No. 11-1999, a silicone-based adhesive is used to bond a silicone-based waterproof gasket to the inside of side edges of a photovoltaic cell on the reverse side thereof.
In bonding a photovoltaic cell to a tile body, an adhesive is applied to the tile body, and the cell, with its second surface downward, is pressed against the resulting adhesive layer. It takes several hours to set the adhesive. If the tile body is moved before the adhesive sets, the photovoltaic cell may possibly be dislocated or lifted. Accordingly, the tile body should be kept stationary until the adhesive set.
In a process for continuously transporting tile bodies by means of a conveyor for mass production and bonding photovoltaic cells individually to the tile bodies during the transportation, each photovoltaic cell is pressed against a layer of an adhesive to be bonded thereto after the adhesive is applied to each tile body. Since the photovoltaic cell is liable to be dislocated before the adhesive sets, however, the photovoltaic cell cannot be transported or can be transported only slowly to the next process, e.g., a caulking process, before the adhesive sets. Thus, satisfactory productivity cannot be enjoyed.
Further, there is a difference in thermal expansion coefficient between the tile body and the photovoltaic cell, and the adhesive may crack due to aging, in some cases. Once a crack is produced, it gradually spreads to cause defective bonding, so that the photovoltaic cell may possibly slip off, thus lacking in reliability.
In a tile of the conventional photovoltaic-cell type, as mentioned before, a photovoltaic cell is fixed directly to a tile body by bonding with an adhesive.
This photovoltaic cell attachment structure is only tight enough to prevent dislocation of a photovoltaic cell module with respect to the tile body at the least. Moreover, lowering of adhesion on the interface between the adhesive and the photovoltaic cell or between the adhesive and the tile is a more serious problem than the aging of the adhesive itself is. If the photovoltaic cell is fanned by a strong wind, it cannot be prevented from lifting, in some cases.
As is described in Jpn. Pat. Appln. KOKAI Publications Nos. 10-88739 or 10-317592, there has been developed a technique that uses a substantially L-shaped metallic fixture besides the adhesive.
More specifically, a part of the L-shaped fixture is fixed to a tile body so that its bent end portion presses down a photovoltaic cell that is fitted in a depression, thereby preventing the cell from lifting off the tile.
However, the fixture is fixed to the tile body. If the fixture restrains the photovoltaic cell from lifting, therefore, all its force is inevitably concentrated on the spot of attachment of the fixture to the tile body, possibly resulting in rupture.
Further, the metallic fixture must be manufactured separately, and fixing the fixture to the tile body and pressing down the photovoltaic cell by means of the fixture require time and labor, inevitably exerting a bad influence upon the cost.
Some photovoltaic cell modules are held in a depression in the upper surface of a tile body. One such module is adhesively bonded to the depression with an adhesive or caulking material or a combination of these materials. Under severe working conditions, such as ones on a roof that is exposed to the heat of the sunlight and the weather, the caulking material or the like may possibly be lowered in quality, so that rainwater may be allowed to get into the depression.
To improve these situations, a novel system is proposed and described in Jpn. Pat. Appln. KOKAI Publication No. 10-88741. According to this system, a photovoltaic cell module is held in a depression in a flat tile, and through holes that open to the reverse side of the flat tile are formed in the lower peripheral edges of the tile so that rainwater in the depression can be discharged to the reverse side of the tile through the through holes.
As mentioned before, however, the rainwater that is discharged to the reverse side of the flat tile through the through holes is received by a directly underlying flat tile and is discharged along the gradient of the tiles. Possibly, therefore, dust or the like may collect in gaps between the overlapping flat tiles and substantially prevent the drainage through the through holes. In this case, there is a high possibility of the rainwater getting into a terminal box for output fetching that is provided on the second surface of the photovoltaic cell module. This problem must be solved in order to ensure reliability in prolonged use.
The object of the present invention is to provide a high-reliability photovoltaic cell module tile in which a photovoltaic cell module can be securely fixed to a tile body.
According to the present invention, there is provided a photovoltaic cell module tile comprising a tile body, a depression provided on the upper surface of the tile body, and a photovoltaic cell module having a terminal box on the lower surface thereof fixed to the base of the depression with an adhesive applied thereto.
According to the invention, moreover, there is provided a photovoltaic cell module tile comprising a tile body, a depression provided in the upper surface of the tile body, and a photovoltaic cell module having a terminal box on the lower surface thereof fixed to the base of the depression by means of a double-coated tape and an adhesive.
According to the invention, furthermore, there is provided a photovoltaic cell module tile comprising a tile body, a depression provided on the upper surface of the tile body, an adhesive pit provided in the depression, a groove continuously extending along at least the upper edge and the opposite side edges of the base of the depression, and a photovoltaic cell module fixedly bonded to the depression in a manner such that an adhesive is applied to the adhesive pit and a sealant is loaded into the groove.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.